The mixture of aggregate, filler, and binder produces Cold Bituminous Emulsion Mixtures (CBEM). CBEM has many several environmental and cost-effective benefits. However, it offers poor early life properties besides achieving maximum strength it required a long curing period. In this experimental study, waste rice husk ash and ordinary Portland cement are used as substitutes for mineral filler with 0%, 1%, 2%, and 3%. The main objective of this study is to improve performance CBEM by combining Waste Rice Husk Ash (WRHA) and Ordinary Portland Cement (OPC). To evaluate enhancement in performance of CBEM, Retained Stability test, Tensile Strength Test, and Marshall Stability Test were conducted. The experimental results show that the tensile strength and Marshall stability of CBEM increased drastically by replacing mineral filler with waste rice husk ash and ordinary Portland cement. The moisture-induced damages are reduced due to the WRHA and OPC is added in the CBEM. As the tensile strength values and stability values of WRHA modified CBEM are more optimistic than OPC modified CBEM.
In every construction project, cost estimation is one of the most crucial aspects that is critical to the project's success. To achieve a proper estimate, price accuracy is fundamental. Building Information Modeling (BIM) is a distinguishing result of the growth of modern information technology in the building industry. Because of its direct quantity extraction features, using BIM in quantity takeoff leads to highly accurate quantities and cost estimation. Meanwhile, there may be few hindrances that lead to errors in price accuracy of BIM-based quantity takeoff. Thus, this study intends to ascertain to which extent the BIM base quantity takeoff is being satisfied with the accuracy of cost estimation by evaluating the impact of BIM-based takeoff advantages and drawbacks for the accuracy of cos estimation and recommending suitable measures to improve the accuracy. To attain the aim, an extensive literature synthesis was piloted to develop a questionnaire survey was carried out upon the key findings of the literature. This paper presents a comprehensive literature review to get an overview of the cost estimation and BIM-based and CAD-based quantity takeoff while identifying the factors affecting accuracy with their advantages and drawbacks. Then the study concludes factors that facilitate increasing the price accuracy with the use of BIM. Later on, twelve possible measures to improve estimating accuracy through BIM-based takeoff were tested in the questionnaire survey. The most significant method was revealed to be equipped estimators with the required software information to prepare more accurate cost estimates using BIM-based quantity takeoff.
Previous repetitive scheduling models were focused on one issue in optimizing project duration or total costs, such as: Interruption, buffer inserting, or acceleration. The main objective of this research is to develop an optimization model which identifies the optimum solution that minimizes total project cost under a group of constraints considering different scenarios for incorporating Interruption, buffer time, and schedule acceleration. Thus, the model user can choose the scenario which best fits his desire. The main contributions of the developed, optimized model are: 1) Scheduling and interruption module capable of optimizing schedules for least total project cost, 2) Scheduling and buffering module of optimizing schedules for least total project cost, 3) A buffering approach that provides a structured tool for building buffers to protect the project schedule from expected delays, 4) A schedule acceleration module that comprises unit-based acceleration algorithm capable of finding least cost of acceleration plans through accelerating units instead of activities, and 5) Queuing criteria for schedule acceleration that allows considering cost slope and contractor's judgment while prioritizing units for acceleration. The developed model is automated using the c # programming language. Thus, the current model is flexible for the user to choose some essential features such as interruption percentage, overtime factor, relative weights allocated to cost slope , and contractor's judgment in acceleration, resulting in saving the user's time suiting large- size projects.
Cost overruns have provided a significant challenge in the construction industries of both developed and developing countries. The purpose of this study was to investigate the influence Subcontractor Oversight on Construction Cost Overruns of real estate projects in Nairobi and Kisumu Counties. The study was guided by objective, to establish the extent to which subcontractor oversight influence real estate construction projects cost overruns. The research adopted descriptive survey and correlational research designs. The study targeted a population of 4000 project professionals that constituted 7 professionals from active real estates in Nairobi and Kisumu Counties and 10 key informants from the real estate industry. Using the Krejcie and Morgan table of sample size determination, the sample size for this study was 351. The study then adopted stratified, simple random and purposive sampling methods to select appropriate sample sizes from the study population strata. Structured questionnaire was the main instrument for data collection, supported by interview guide. Hypothesis was tested at α=0.05 level of significance and the results were: H0: There is no significant relationship between subcontractor oversight and real estate construction projects cost overruns was rejected since P=0.000<0.05. Considering the study findings and conclusions, the following recommendations were made: Project professionals and other relevant real estate project stakeholders should encourage comprehensive subcontractor oversight as critical concerns in assembling pertinent information and creating avenues that could be utilized to reduce real estate construction projects cost overruns.
